noCache: use cache or not. Cache could make template rendering 100x faster than without cache. It useful for production, but useless for development (pages would not be updated untill Koa restarted). In most case, noCache: process.env === 'development' should be enough. If wanna control it in production for specific page, use render()'s noCache instead.

helperPath: String or Array, where to load helpers, and make them available on all .jade. In Array, you can use object to assgin name for module, eg: { random: './path/to/random.js' }.

basedir: help Jade to identify paths when using extends with absolute paths.

If options is set to true or false, it will be treated as noCache, and noCache will be ignored. For example, render(tpl, locals, true) equals to render(tpl, locals, {}, true), and render(tpl, locals, true, false) will skip cache and re-compile template.